Having this issue while setting up the Kafka Cluster using Kraft
server.properties
Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the “License”); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an “AS IS” BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# This configuration file is intended for use in KRaft mode, where
# Apache ZooKeeper is not present.
#
############################# Server Basics #############################
# The role of this server. Setting this puts us in KRaft mode
process.roles=broker,controller
# The node id associated with this instance’s roles
node.id=1
# The connect string for the controller quorum
[email protected]:9093,[email protected]:9093,[email protected]:9093
############################# Socket Server Settings #############################
# The address the socket server listens on.
# Combined nodes (i.e. those with process.roles=broker,controller) must list the controller listener here at a minimum.
# If the broker listener is not defined, the default listener will use a host name that is equal to the value of java.net.InetAddress.getCanonicalHostName(),
# with PLAINTEXT listener name, and port 9092.
# FORMAT:
# listeners = listener_name://host_name:port
# EXAMPLE:
# listeners = PLAINTEXT://your.host.name:9092
#listeners=PLAINTEXT://kafka-contabo-vps.netbird.cloud:9092,CONTROLLER://kafka-contabo-vps.netbird.cloud:9093
# Name of listener used for communication between brokers.
# inter.broker.listener.name=SASL_PLAINTEXT
# Listener name, hostname and port the broker or the controller will advertise to clients.
# If not set, it uses the value for “listeners”.
#advertised.listeners=PLAINTEXT://kafka-contabo-vps.netbird.cloud:9092
# A comma-separated list of the names of the listeners used by the controller.
# If no explicit mapping set in listener.security.protocol.map, default will be using PLAINTEXT protocol
# This is required if running in KRaft mode.
controller.listener.names=CONTROLLER
# Maps listener names to security protocols, the default is for them to be the same. See the config documentation for more details
#listener.security.protocol.map=CONTROLLER:PLAINTEXT,PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL
# The number of threads that the server uses for receiving requests from the network and sending responses to the network
num.network.threads=3
# The number of threads that the server uses for processing requests, which may include disk I/O
num.io.threads=8
# The send buffer (SO_SNDBUF) used by the socket server
socket.send.buffer.bytes=102400
# The receive buffer (SO_RCVBUF) used by the socket server
socket.receive.buffer.bytes=102400
# The maximum size of a request that the socket server will accept (protection against OOM)
socket.request.max.bytes=104857600
############################# Log Basics #############################
# A comma separated list of directories under which to store log files
log.dirs=/home/kafka/kafka-logs
# The default number of log partitions per topic. More partitions allow greater
# parallelism for consumption, but this will also result in more files across
# the brokers.
num.partitions=6
# The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
# This value is recommended to be increased for installations with data dirs located in RAID array.
num.recovery.threads.per.data.dir=1
############################# Internal Topic Settings #############################
# The replication factor for the group metadata internal topics “__consumer_offsets” and “__transaction_state”
# For anything other than development testing, a value greater than 1 is recommended to ensure availability such as 3.
offsets.topic.replication.factor=2
transaction.state.log.replication.factor=2
transaction.state.log.min.isr=2
############################# Log Flush Policy #############################
# Messages are immediately written to the filesystem but by default we only fsync() to sync
# the OS cache lazily. The following configurations control the flush of data to disk.
# There are a few important trade-offs here:
# 1. Durability: Unflushed data may be lost if you are not using replication.
# 2. Latency: Very large flush intervals may lead to latency spikes when the flush does occur as there will be a lot of data to flush.
# 3. Throughput: The flush is generally the most expensive operation, and a small flush interval may lead to excessive seeks.
# The settings below allow one to configure the flush policy to flush data after a period of time or
# every N messages (or both). This can be done globally and overridden on a per-topic basis.
# The number of messages to accept before forcing a flush of data to disk
#log.flush.interval.messages=10000
# The maximum amount of time a message can sit in a log before we force a flush
#log.flush.interval.ms=1000
message.max.bytes=104857600
replica.fetch.max.bytes=104857600
############################# Log Retention Policy #############################
# The following configurations control the disposal of log segments. The policy can
# be set to delete segments after a period of time, or after a given size has accumulated.
# A segment will be deleted whenever either of these criteria are met. Deletion always happens
# from the end of the log.
# The following configurations control the disposal of log segments.
# The minimum age of a log file to be eligible for deletion due to age
log.retention.hours=168
# Set a size-based retention policy for logs (100GB)
log.retention.bytes=107374182400
# The maximum size of a log segment file. When this size is reached a new log segment will be created.
log.segment.bytes=1073741824
# The interval at which log segments are checked to see if they can be deleted according to the retention policies
log.retention.check.interval.ms=300000
# Correct listeners configuration
listeners=SASL_PLAINTEXT://kafka-contabo-vps.netbird.cloud:9092,CONTROLLER://kafka-contabo-vps.netbird.cloud:9093
advertised.listeners=SASL_PLAINTEXT://kafka-contabo-vps.netbird.cloud:9092
# Ensure security protocols are correctly mapped
listener.security.protocol.map=CONTROLLER:PLAINTEXT,SASL_PLAINTEXT:SASL_PLAINTEXT
# Inter-broker communication must also use SASL_PLAINTEXT
inter.broker.listener.name=SASL_PLAINTEXT
# Enable SASL mechanisms
sasl.enabled.mechanisms=PLAIN
sasl.mechanism.inter.broker.protocol=PLAIN
error
[2025-02-07 09:05:59,944] INFO [SocketServer listenerType=BROKER, nodeId=1] Failed authentication with /100.104.252.202 (channelId=100.104.196.144:9092-100.104.252.202:35256-620) (Unexpected Kafka request of type METADATA during SASL handshake.) (org.apache.kafka.common.network.Selector)
[2025-02-07 09:06:00,379] INFO [SocketServer listenerType=BROKER, nodeId=1] Failed authentication with /100.104.252.202 (channelId=100.104.196.144:9092-100.104.252.202:55944-620) (Unexpected Kafka request of type METADATA during SASL handshake.) (org.apache.kafka.common.network.Selector)
[2025-02-07 09:06:01,394] INFO [SocketServer listenerType=BROKER, nodeId=1] Failed authentication with /100.104.98.28 (channelId=100.104.196.144:9092-100.104.98.28:33934-621) (Unexpected Kafka request of type METADATA during SASL handshake.) (org.apache.kafka.common.network.Selector)
[2025-02-07 09:06:01,431] INFO [SocketServer listenerType=BROKER, nodeId=1] Failed authentication with /100.104.252.202 (channelId=100.104.196.144:9092-100.104.252.202:55952-621) (Unexpected Kafka request of type METADATA during SASL handshake.) (org.apache.kafka.common.network.Selector)
[2025-02-07 09:06:01,703] INFO [SocketServer listenerType=BROKER, nodeId=1] Failed authentication with /100.104.252.202 (channelId=100.104.196.144:9092-100.104.252.202:35264-622) (Unexpected Kafka request of type METADATA during SASL handshake.) (org.apache.kafka.common.network.Selector)
[2025-02-07 09:06:01,755] INFO [SocketServer listenerType=BROKER, nodeId=1] Failed authentication with /100.104.252.202 (channelId=100.104.196.144:9092-100.104.252.202:49798-621) (Unexpected Kafka request of type METADATA during SASL handshake.) (org.apache.kafka.common.network.Selector)
[2025-02-07 09:06:02,494] INFO [SocketServer listenerType=BROKER, nodeId=1] Failed authentication with /100.104.252.202 (channelId=100.104.196.144:9092-100.104.252.202:55958-622) (Unexpected Kafka request of type METADATA during SASL handshake.) (org.apache.kafka.common.network.Selector)